JesseYan

数据库相关查询优化

1.对查询进行优化，应尽量避免全表扫描，首先应考虑在 where 及 order by 涉及的列上建立索引。
2.应尽量避免在 where 子句中对字段进行 null 值判断，否则将导致引擎放弃使用索引而进行全表扫描，如：
select id from t where num is null
可以在num上设置默认值0，确保表中num列没有null值，然后这样查询：
select id from t where num=0
3.应尽量避免在 where 子句中使用!=或<>操作符，否则将引擎放弃使用索引而进行全表扫描。
4.应尽量避免在 where 子句中使用 or 来连接条件，否则将导致引擎放弃使用索引而进行全表扫描，如：
select id from t where num=10 or num=20

JesseYan

// UpsertByDwIndicatorID 创建或者更新,返回最新的数据
func UpsertByDwIndicatorID(d *model.BiIndicator) error {
	var err error
	if nil == d || 0 == d.DwIndicatorID {
		return errors.New("UpsertByDwIndicatorID error: BiIndicator nil or DwIndicatorID value is empty")
	}

	if _, err := QueryOne([]basemodel.Pair{
		{K: "dw_indicator_id", V: d.DwIndicatorID},

JesseYan

//SendEmail 发送邮件
func SendEmail(conf *EmailConfig) error {
	m := gomail.NewMessage()
	m.SetHeader("From", conf.From)
	m.SetHeader("To", conf.To...)
	m.SetHeader("Subject", conf.Subject)
	if conf.ContentType == EmailTextType {
		m.SetBody("text/plain", conf.ContentBuffer.String())
	} else if conf.ContentType == EmailHTMLType {
		m.SetBody("text/html", conf.ContentBuffer.String())

JesseYan

func spectreCase() error {
	host := os.Getenv("SPECTRE_HOST")
	key := os.Getenv("SPECTRE_KEY")
	secret := os.Getenv("SPECTRE_SECRET")
	if host == "" || key == "" || secret == "" {
		fmt.Println("Error 环境变量SPECTRE_HOST、SPECTRE_KEY、SPECTRE_SECRET均不能为空")
	}
	var bucketName = "venus-table-bucket-test"
	//var bucketName = "venus-table-bucket" //online

JesseYan

package goroutinetimeout

import (
	"context"
	"encoding/json"
	"fmt"
	"testing"
	"time"

	"proto/bi/service/olap/service"

JesseYan

proto define

message Sheet {
	string sheet_name=1;
	repeated Line lines=2;
}

message Line {
	repeated Cell cells=1;
}

JesseYan

package main

import (
	"fmt"
	"time"
)

func main() {
	ch := make(chan int, 4)
	go write(ch)

JesseYan

package main

import (
	"fmt"
	"sync"
	"time"
)

var wg sync.WaitGroup